Ethyl formate → 4-cyclopropyl-1H-pyrazol-3-amine

Participants

Reaction Steps

To 7 g (0.3 mol) of freshly cut sodium chunks in 220 mL dry ether under nitrogen and external ice cooling was added a solution of 25 mL (0.3 mol) ethyl formate followed by a solution of 25 g (0.3 mol) cyclopropylacetonitrile in 50 mL dry ether, and the mixture was stirred at room temperature for 2 days. 19 mL (0.3 mol) glacial acetic acid was added whilst maintaining the internal temperature at 10-12° C., the solids were filtered off and the filtrate was concentrated at below 20° C. The residue was treated with 300 mL (0.6 mol) 2 M hydrazine in THF, 5 mL glacial acetic acid and heated at reflux for 2 hours. After cooling, the mixture was concentrated and the desired product was obtained by kugelrohr distillation. The product was used in the next step without further purification.

Provenance & Evidence